FIGS. 1-4 illustrate a conventional household appliance 100, such as a front-loading clothes washer, having a housing 110 and a door 112 to provide access to the interior of the appliance housing 110. The housing 110 encloses a washing unit, which includes a tub 210 having a rotating washing drum 215 that rotates or oscillates about an axis to move the clothes or laundry in the tub 210. A drive system rotates or oscillates the rotating washing drum 215 within the tub 210 about the axis of the drum 215. The drive system can include, for example, a motor 214, a pulley 216, and a drive belt 218. The interior of the tub 210 is accessible through the opening 212, which corresponds to the door 112 of the housing 110, as illustrated in FIG. 1. In operation, clothes or laundry are inserted into the washer 100 through the door 110 and placed in the rotating washing drum 215 inside the tub 210. The household appliance 100 wets the laundry to be washed with a fluid, such as a washing liquid, rinsing liquid, water, or other fluid, and mechanically moves the laundry to release contaminants from the laundry.
As shown in FIGS. 2-4, the tub 210 can include a heater pocket 300 having a heating element 400 disposed therein. The washing unit also can include a drain assembly 220 coupled to or formed in the tub 210. The drain assembly 220 can be in fluid communication with the heater pocket 300. The drain assembly 220 can include, for example, a discharge pump (not shown) and corrugated tube for discharging the fluid from the tub 210.
With reference again to FIG. 4, an example of a conventional heater pocket 300 includes a first sidewall 302, a second sidewall 304, and a bottom wall 306. A plate 502 can be coupled to or integrally formed with the bottom wall 306 of the heater pocket 300. A heater coil retainer clip 402 can be coupled to the plate 502. During assembly of the household appliance, a heating element 400 having heater coils 404 and a fixation base 406 can be inserted into and sealingly engaged with an opening at the far end of the heater pocket 300, as viewed in FIG. 4. The heater coils 404 engage and are retained by the heating element retainer clip 402.
The interior surface of the bottom wall 306 can be sloped in a direction toward the drain assembly 220 to promote the flow of the fluid toward and into the drain assembly 220, as shown in FIG. 2. The drain assembly 220 (not shown in FIG. 4) is located at the near end of the heater pocket 300 as viewed in FIG. 4 (i.e., at an opposite end from the base 406 of the heating element 400). An opening into the drain assembly from the heater pocket can include a mesh screen, for example a metal screen, that prevents or reduces the flow of debris from the heater pocket 300 into the drain assembly.
FIG. 4 illustrates a cross-section of a conventional heater pocket taken in a direction substantially perpendicular to the axis of rotation of the drum 215. In the cross-section of the heater pocket 300, the first sidewall 302 and the second sidewall 304 of the heater pocket 300 are not perpendicular to the bottom wall 306. That is, the first sidewall 302 and the second sidewall 304 of the heater pocket 300 can be inclined at an angle other than 90° with respect to the bottom wall 306. For example, when viewed in cross-section, the first sidewall 302 can be inclined by a first angle and the second sidewall 304 can be inclined at a second angle with respect to the bottom wall 306. Other conventional heater pockets may include sidewalls that are perpendicular to the bottom wall 306.
FIGS. 5 and 6 schematically illustrate a conventional arrangement of a tub 210 and heater pocket 300 having a heating element 400 including a heater coil 404 and fixation base 406. The heater coil 404 is secured in the heater pocket 300 by the heating element retainer clip 402. The radii of the heater pocket 300 are indicated by dashed lines 301.
During operation, the rotation of the drum 215 induces flow F of the fluid into the heater pocket 300 in a first direction. The drum 215 can include paddle-shaped elements thereon for lifting or pushing the fluid as the drum 215 rotates, thereby inducing flow F of the fluid into the heater pocket in a first direction and then out of the other side of the heater pocket. During a heating cycle, the fluid flows from the drum 215 into the heater pocket 300, wherein the heater coils transfer heat to the fluid. The heated fluid then flows out of the heater pocket 300 and back into the drum 215. Similarly, during a rinsing cycle, the fluid flows from the drum 215 into the heater pocket 300 and then out of the heater pocket 300 and back into the drum 215. During the heating and/or rinsing cycles, the drum 215 may rotate in a first direction (e.g., a clockwise direction shown by flow F) for a period of time, and then rotate in a second direction (e.g., a counter-clockwise direction) for a period of time.
During a draining cycle of the washer, for example a spinning cycle, the drain is opened and the fluid is intended to flow from the drum 215 into the heater pocket 300 (flow F), and then is permitted to flow into, or be drawn into, the corrugated tubing of the drain assembly 220. As explained above, a discharge pump can be provided for drawing the fluid from the heater pocket 300 and the tub 210 into the drain assembly 220. During the draining cycle, the drum 215 may rotate in a single direction such that the fluid flows into the heater pocket 300 in a single direction, for example, a clockwise direction in FIGS. 1-4 (flow F).
The heating element 400 having heater coils 404 and a base 406, as well as the heating element retainer clip 402, commonly include features, such as sharp corners, edges, etc., that may be prone to collecting or accumulating debris, such as fluffs (e.g., lint or paper particles) and deposits or formation of lime.